make it up as one goes along

a little of something goes a long way

Only a small amount of something is usually required to produce a great effect.

anything goes

There are no rules or restrictions.

as best one can

In the best possible way, given one's circumstances and abilities.

as far as one knows

To the best of one's knowledge, as far as someone knows or possible information to be gathered about the topic, subject, aspect, or situation.

back to square one

Located back at the start, as after a dead end or failure.

balloon goes up

Something exciting, risky, or troublesome begins.

beat as one

To share the same feelings.

become one flesh

To join together in marriage; to develop a unifying bond as a result of marrying.